Nanoparticles to Track T Cell Immunotherapy Using Magnetic Particle Imaging

项目摘要 过继性细胞转移（ACT）T细胞免疫疗法在实体癌中成功的关键一步是实现 T细胞在肿瘤部位的运输和持久性，同时避免由于T细胞攻击脱靶而引起的毒性 组织和器官。非侵入性定量成像将是一个强大的工具，以了解机制， T细胞免疫疗法的作用和失败，评估T细胞修饰和递送途径的影响， 监测脱靶T细胞积累，并根据T细胞肿瘤的测量结果对治疗反应进行分层 积累这个生物工程研究资助项目将开创非侵入性和定量跟踪， 采用磁粒子成像（MPI）的过继性T细胞癌免疫治疗，一种新的分子成像模式 这使得非侵入性的，明确的，和断层分析的全身分布， 超顺磁性氧化铁纳米颗粒（SPION）。初步结果显示， 定量追踪颅内实体肿瘤中的ACT T细胞，合成具有增强的MPI灵敏度的示踪剂， 和5x 103个T细胞的电流敏感性。这项工作旨在提高对5x 102个T细胞的敏感性， 证明了MPI在定量癌症小鼠模型中T细胞生物分布中的准确性。建模 PI的MPI物理表明，MPI的最佳示踪剂必须具有均匀的物理和磁性 性能和低磁晶各向异性，使快速偶极开关在大SPION直径。的 PI开发了一种新的合成方法，可以产生无缺陷的SPION，具有均匀的磁性能和低成本。 磁晶各向异性所提出的工作（目标1）将耦合这种新的合成与建模的MPI 物理和全面的物理和磁性表征，以获得对 SPION性质与MPI性能之间的关系，并获得具有上级灵敏度的SPION。成像 追踪T细胞的方法必须不损害它们的活力或功能，而T细胞构成了独特的挑战 用于纳米颗粒标记。所提出的工作（目标2）将定义用以下标记原代T细胞的上限： MPI示踪剂使用通过电荷与T细胞结合的示踪剂，不影响活力或功能 交互.初步研究证明了使用MPI非侵入性跟踪小鼠中的T细胞生物分布， 以及SPION标记的T细胞在小鼠模型中全身给药后到达实体瘤。拟议 本工作（目标3）将验证使用MPI的ACT T细胞治疗的体内跟踪与使用流式细胞仪的T细胞计数的对比。 图1示出了细胞计数的结果，并将使用MPI纵向评估肿瘤中T细胞积累的动力学。拟议 PI（SPION和MPI）的互补专业知识使生物材料开发研究计划成为可能 物理学）和Co-I（ACT T细胞疗法），并获得最先进的仪器来表征SPION 离体和体内MPI性能。达到5x 102 T细胞的目标灵敏度将提供一个 定量细胞跟踪灵敏度相对于其他全身定量成像的显著提高 技术，建立MPI作为一个强大的工具，在免疫成像工具箱。

Project Summary A critical step in the success of adoptive cell transfer (ACT) T cell immunotherapy in solid cancers is achieving trafficking and persistence of T cells at tumor sites, while avoiding toxicities due to T cell attack of off-target tissues and organs. Non-invasive quantitative imaging would be a powerful tool to understand mechanisms of action and failure of T cell immunotherapies, evaluate the impact of T cell modifications and delivery routes, monitor off-target T cell accumulation, and stratify response to therapy on the basis of measures of T cell tumor accumulation. This Bioengineering Research Grant project will pioneer non-invasive and quantitative tracking of adoptive T cell cancer immunotherapy using magnetic particle imaging (MPI), a new molecular imaging modality that enables non-invasive, unambiguous, and tomographic analysis of the whole-body distribution of superparamagnetic iron oxide nanoparticles (SPIONs). Preliminary results demonstrate non-invasive quantitative tracking of ACT T cells in solid intracranial tumors, synthesis of tracers with enhanced MPI sensitivity, and current sensitivity of 5x103 T cells. The proposed work aims to improve sensitivity to 5x102 T cells and demonstrate the accuracy of MPI in quantifying T cell biodistribution in mouse models of cancer. Modeling of MPI physics by the PI demonstrates that tracers optimal for MPI must have uniform physical and magnetic properties and low magnetocrystalline anisotropy, to enable fast dipole switching at large SPION diameters. The PI has developed a new synthesis that yields defect-free SPIONs with uniform magnetic properties and low magnetocrystalline anisotropy. The proposed work (Aim 1) will couple this new synthesis with modeling of MPI physics and comprehensive physical and magnetic characterization to gain fundamental understanding of the relation between SPION properties and MPI performance and to obtain SPIONs with superior sensitivity. Imaging approaches to track T cells must not compromise their viability or function and T cells pose unique challenges for nanoparticle labeling. The proposed work (Aim 2) will define an upper limit for labeling primary T cells with MPI tracers without compromising viability or function using tracers that associate with T cells through charge interactions. Preliminary studies demonstrate non-invasive tracking of T cell biodistribution in mice using MPI, and that SPION-labeled T cells reach solid tumors after systemic administration in murine models. The proposed work (Aim 3) will validate in vivo tracking of ACT T cell therapy using MPI against T cell counting using flow cytometry and will evaluate dynamics of T cell accumulation in tumors longitudinally using MPI. The proposed biomaterials-development research plan is enabled by the complementary expertise of the PI (SPIONs and MPI physics) and Co-I (ACT T cell therapies) and access to state-of-the-art instrumentation to characterize SPION MPI performance ex vivo and in vivo. Achieving the target sensitivity of 5x102 T cells will provide an order-of- magnitude improvement in quantitative cell tracking sensitivity over other whole body quantitative imaging technologies, establishing MPI as a powerful tool in the immunoimaging toolbox.